Don't blame it all on global climate change

Recently, I was astonished to read a paper published by a prestigious institution that stated -- without qualification -- that Colorado's current bark beetle epidemic could be pinned on the donkey of climate change. More amazing yet, this paper said that Vail Resorts now seeds clouds because of the unreliable snow caused by climate change.

What's next, I wondered: Was I going to be told that the Great Recession was a consequence of warming temperatures? The diabetes epidemic? The hailstorm that took out my garden last June?

The report came from Harvard and profiled a Colorado company known for its environmental activism, but it's indicative of what I hear frequently among those worried about global warming. There's a tendency among activists to cherry-pick facts, to overstate their case. To an extent, this is understandable. We like simple stories. Our eyes glaze over with equivocators like "maybe" and "possibly," let alone laundry lists of explanations.

But too much over-simplification leaves activists looking crazy eyed, not much better than those who want to reject the increasingly compelling theory of global climate change based on last week's weather in their own backyard. The science is strong enough to stand on its own feet. It serves no good purpose to prune facts from the storyline.

Consider cloud seeding. Vail Resorts may seed clouds today because of the changing climate, but that wasn't a given when it began doing so after the snowless winter of 1976-'77. Joe Macy, the representative of the company, which was then based in Vail, Colo., showed up every year in the '80s to ask the local town councils to pitch in, and they always did. Nobody ever mentioned climate change.

As for bark beetles, the warming winters undoubtedly have given them a boost. Thirty or 40 years ago, winters were more often spiked by severe cold. I remember the thermometer at Bob's 66 filling station in Kremmling, Colo., plunging to 60 below the first Tuesday morning of 1979. It didn't rise above zero all week. I had a union suit then, and I wore it for weeks at a spell. There are some things about the good old days I don't miss a bit.

But the severity of the current epidemic surely has multiple authors: Drought in 2002-2004 made trees more vulnerable. So did the simple progression of age and a half-century of fire suppression. One scientific paper correlates drought to 500-year warming cycles in the Atlantic Ocean. Of course, the Ivy League paper mentioned none of these nuances.

Examination of weather records for the last several decades reveals that Colorado warmed during the last 10 years, but not dramatically. "Almost anywhere we go in the state, there has been a some upward motion in temperature -- not very profound or dramatic anywhere, but some small warming most everywhere," says Nolan Doesken, the state climatologist at Colorado State University. Precipitation levels of the last decade also had changed little from the 1970s, he says. "It is a hard one for me to buy that climate is the sole driver of that problem or even the primary driver."

This may be the most severe bark beetle epidemic in our recorded history, but that doesn't go back very far. Fires leave traces in lieu of written records - and there have been some big ones in the centuries before record-keeping began. Past beetle epidemics are more difficult to discern.

Even within current human lifetimes, however, we've had major beetle epidemics. A few spruce snags remain from the greater infestation of the 1940s and early 1950s. And immediately on the heels of that cold weather that had me shivering in the late '70s came a beetle epidemic, if admittedly lesser in scope.

Climate change is worrisome, maybe even an emergency. The Dust Bowl was far smaller in scope, but caused vast misery, even as it also inspired some of our nation's greatest art. Growing up 20 to 30 years afterward, there was a bit of that lingering grit in my family's conversation. Now, accumulating greenhouse gases may make that grit seem a minor annoyance in comparison. But throwing everything into the lap of global warming does nothing to strengthen the credibility of global warming activists. At times, I wish they'd just chill out.

Allen Best is a contributor to Writers on the Range, an op ed service of High Country News (hcn.org). He writes about water, energy and other natural resource issues from Denver.

Note: the opinions expressed in this column are those of the writer and do not necessarily reflect those of High Country News, its board or staff. If you'd like to share an opinion piece of your own, please write Betsy Marston at betsym@hcn.org.